Agriculture - Hay

Hay is grass that has been cut then dried in the summer months, and then been stored for use in the winter when the grass is not available. The grass is dried to a moisture content below which mould does not develop. This allows it to be stored under cover, but without wrapping or packing.  

There are two general categories of hay: seed hay and meadow hay. Seed hay is made from grass mixtures specially grown for hay production. Italian or perennial ryegrass, timothy and specialist blends of them are all commonly available forms of seed hay. It generally tends to be quite coarse in nature, with a relatively low nutritive value. Meadow hay is cut from permanent pasture, and usually compromises a more varied mixture of grass species than that specially sown. Generally, meadow hay has a higher nutritive value than seed hay.

Very little hay grown in damper climes of Britain is entirely dust free. The dust consists mainly of mould spores from the field or barn spoilage.  In the UK it is common practice to soak or steam hay before giving it to your horse. 

Soaking the hay causes the dust spores to either be washed off or to swell and stick to the grass storks, meaning that they are ingested rather than being inhaled. Soaking hay requires a lot of time and water and space - in the winter the water can become frozen whilst in summer the water can become brackish.  Undersoaking hay may not remove the spores whilst over soaking hay will result in some nutrient loss.   Soaking hay for 30 minutes will be sufficient to remove the dust spores.

Steaming Hay is another method for removing spores, moulds, bacteria and dust mites.  Steaming works by killing off the dust and fungal spores.  You can buy specialist steamers which can steam a small bale of hay (c. 18-20kg) at a time or alternatively some people use various DIY methods in including filling a net, placing it inside a plastic dustbin, pouring over 1-2 kettles of boiling water, putting the lid on and waiting for between 10-20 minutes.

I once made my own steamer using a large water butt (£10), wallpaper steamer (£20) and drilling a hole in the bottom of the waterbutt and putting the steamer pipe through the hole – I also propped the haynets up on top of a wire basket at the bottom of the waterbutt to ensure the steam could penetrate all of the hay.    The waterbutt was sufficiently big that I could steam two large nets at a time.  Obviously when using a home-made steamer care needs to be taken with electrics, boiling hot water and steam, ensuring that the steamer doesn’t run dry, (health and safety etc).

But overall it did the job well and the hay came out smelling lovely and it was dust free.  That said, the farmer was none too pleased about the additional electricity cost (all 10 minutes of it).  He’d of preferred we filled baths full of water as the water was from source, so free!

Reference: http://www.bow-wow-pets.co.uk/blog/understanding-forage-grass-hay-haylage.html